Fine wire clamp



March 2, 1965 H. J. GROODY FINE WIRE CLAMP Filed Aug. 20, 1962 FXG. 2.

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INVENTOR HAROLD GROODY ATTORNEY United States Patent Ofi ice 3,171,799 Patented Mar. 2, 1865 3,171,709 FINE W (ZLAMP Harold J. Groody, Costa Mesa, Califi, assignor to Beekman Instruments, the, a corporation of California Filed Aug. 20, 1962, Ser. No. 217,809 2 Qlaims. ('Cl. 339-259) This invention relates to a clamp member for mechanically gripping and/ or electrically contacting wire or other materials of very small diameter or thickness.

It is frequently necessary to mechanically grip or electrically contact fine wire of very small diameter, such as wire having a diameter of the order of magnitude of .004 inch or smaller. The standard alligator clip cannot be used for clamping very small diameter wire without filing away the teeth of the clip, which is a very difficult and time-consuming operation. Furthermore, even when the teeth of the alligator clip are filed, it is extremely diificult to make the jaws of the clip exactly parallel, with the result that the fine wire slips out of the clip unless the wire is placed in the clip exactly where the jaws touch each other.

Another type of clip which is known for gripping and contacting fine wires includes two opposing flat spring like leaves. However, this type of clip is also unsatisfactory in use since the leaves of the clip do not remain parallel and hence the fine wire slips out of the clip.

Accordingly, it is an object of this invention to provide a new and improved clip for mechanically gripping and/ or electrically contacting fine wires or other materials of small diameter or thickness.

Another object of the invention is to provide a clamp for mechanically gripping and/or electrically contacting fine wires which does not require close tolerances in its manufacture and which is easily manufactured.

It is another object of the invention to provide a clamp for fine wires or the like which may be easily moved to open position to either receive or release the wire and which firmly grips the wire when the clamp is in closed position.

In aclt'evement of these objectives, there is provided in accordance with an embodiment of this invention a clamp member including a pair of metal jaws pivotally connected intermediate the forward and rear ends thereof and which open at their forward ends against the force of a biasing spring when manual pressure is exerted on the rear ends of the jaws. A helical coil of resilient electrically conductive material is positioned between the for ward ends of the jaws and the fine wire or other material which is to be gripped and/ or electrically contacted may be positioned between adjacent turns of the helical coil when manual pressure is exerted to open the jaws and thereby separate the turns of the helical coil. When manual pressure is released to permit the jaws to close, the fine wire is firmly gripped between the adjacent turns of the compressed helical coil.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing in which:

FIG. 1 is a perspective view of a clamp member in accordance with the invention, the clamp member being shown in closed position and gripping a fine wire;

FIG. 2 is a side elevation view of the clamp member of FIG. 1, with the clamp member in closed position; and

FIG. 3 is a side elevation view of the clamp in open position.

Referring now to the drawing, the clamp member of the invention is generally indicated at and includes a pair of jaws 12 and 14 which are mounted for pivotal movement with respect to each other on a pin 16 located inter mediate the lengths of the jaws and extending transversely of the lengths thereof. laws 12 and 14 are formed of copper or other suitable electrically conductive material. law 12 has a terminal sleeve 18 formed at the rear end thereof, and an electrical conductor 26 is suitably electrically and mechanically connected to terminal sleeve 18. A torsion spring 22 is positioned on pin 16, and the opposite ends of the torsion spring bear against the inner surfaces of the respective jaws 12 and 14 to exert a force which moves the forward ends 24 and 26 of the jaws toward closed position. These forward ends are equipped with teeth 27 in the manner of the standard alligator clip. it will be apparent from the description below that these teeth may be deleted if the clamp is to be used to grip fine wires only.

In accordance with the invention, a helical coil 28 formed of resilient electrically conductive material is interposed between forward ends 24 and 26 of the two jaws. The opposite axial ends of coil 28 are suitably secured mechanically and electrically to the ends 24 and 25 of the jaws.

In using the clamp member to grip a fine wire or the like, manual pressure is exerted on the knurled thumbpiece Bill at the rear end of upper jaw 14 to move the jaws to open position as seen in FIG. 3 against the force of torsion spring 22-. Opening of jaws 12 and 14 axially stretches resilient helical coil 23 and separates the adjacent turns of the helical coil to permit insertion between two adjacent turns of the coil of the fine wire W or other material to be gripped. When manual pressure is released from the clamp, torsion spring 22, with some help from helical coil 23, causes jaws 12 and i l to return to the closed position shown in FIGS. 1 and 2 in which helical coil 28 is compressed and the wire XV is firmly gripped between two adjacent turns of the helical coil. Wire W may be released from engagement with the turns of helical coil 28 by again exerting pressure on thumbpiece 30 of jaw 14 to open the forward ends of the jaws and permit removal of the wire from the separated turns of coil 28.

The clamp member hereinbefore described provides a small area of contact between helical coil 28 and wire W or other material being held, resulting in high local pressure on the wire which causes the wire to be held very firmly. The rounded surfaces of the turns of the helical coil which grip the wire being held prevent breakage of the wire. Therefore, the clamping device not only pro vides good electrical contact with the wire or other material being held, but also securely mechanically grips the wire and permits the clamping device to be used for the purpose of stretching small diameter wires and holding them taut.

While the invention has been described as embodied in a wire clamp, it may be used to clamp non-metallic materials such as thread, yarn, or hair, and may also be used to grip paper, rubber or plastic sheet, and foil or shim stock.

While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and, therefore, it is aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as my invention is:

1. A clamp for gripping and electrically contacting materials of small diameter or thickness comprising a pair of jaw members, means connecting said jaw members for movement relative to each other, spring means biasing a pair of corresponding ends of said jaw members toward each other, a helical coil of resilient electrically conductive material interposed between and mechanically connected at the opposite axial ends thereof to said corresponding ends of said jaw members, said helical coil having adjacent turns thereof in juxtaposition with respect to each other, an electrical terminal carried by said clamp, and means conductively connecting said helical coil to said electrical terminal, whereby opening of said jaw members against the force of said spring means causes separation of the turns of said coil' to permit insertion between adjacent turns of said coil of the material to be gripped and electrically contacted.

2. A clamp for gripping and electrically contacting materials of small diameter or thickness comprising a pair of jaw members, means connecting said jaw members for movement relative to each other, spring means biasing a pair of corresponding'ends of said jaw members toward each other, a helical coil of resilient electrically conductive material interposed between and mechanically connected at the opposite axial ends thereof to said corresponding ends of said jaw members, said helical coil having adjacent turns thereof in juxtaposition with respect to each other, at least one of said jaw members being formed of electrically conductive material, an electrical terminal carried by said clamp and conductively connected to at least said one jaw member, said helical coil being conductively connected to at least said one jaw member, whereby opening of said jaw members against the force of said spring means causes separation of the turns of said coil to permit insertion between adjacent turns of said coil of the material to be gripped and electrically contacted.

References Cited in the file of this patent 

1. A CLAMP FOR GRIPPING AND ELECTRICALLY CONTACTING MATERIALS OF SMALL DIAMETER OR THICKNESS COMPRISING A PAIR OF JAW MEMBERS, MEANS CONNECTING SAID JAW MEMBERS FOR MOVEMENT RELATIVE TO EACH OTHER, SPRING MEANS BIASING A PAIR OF CORRESPONDING ENDS OF SAID JAW MEMBERS TOWARD EACH OTHER, A HELICAL COIL OF RESILIENT ELECTRICALLY CONDUCTIVE MATERIAL INTERPOSED BETWEEN AND MECHANICALLY CONNECTED AT THE OPPOSITE AXIAL ENDS THEREOF TO SAID CORRESPONDING ENDS OF SAID JAW MEMBERS, SAID HELICAL COIL HAVING ADJACENT TURNS THEREOF IN JUXTAPOSITION WITH RESPECT TO EACH OTHER, AN ELECTRICAL TERMINAL CARRIED BY SAID CLAMP, AND MEANS CONDUCTIVELY CONNECTING SAID HELICAL COIL TO SAID ELECTRICAL TERMINAL, WHEREBY OPENING OF SAID JAW MEMBERS AGAINST THE FORCE OF SAID SPRING MEANS CAUSES SEPARATION OF THE TURNS OF SAID COIL TO PERMIT INSERTION BETWEEN ADJACENT TURNS OF SAID COIL OF THE MATERIAL TO BE GRIPPED AND ELECTRICALLY CONTRACTED. 